There is an autonomous personal service robot disclosed in U.S. Pat. No. 7,228,203 for mainly monitoring the condition of surrounding environment, such as smoke, heat and CO2 content, and addressing the functions of medicine supply, blood pressure measurement, and connection with refrigerator and stereo system. However, the robot is weak in monitoring a person to be nursed, making it infeasible to get hold of timely physical complaint of the person to be nursed.
Besides, there is also a medical tele-robotic system disclosed in U.S. Pat. No. 7,218,992, in which the system contains a robotic arm, and communication interfaces, e.g. a monitor, a webcam, etc., enabling to remotely remind a person to be nursed to take medicine. It mainly lies in that the robotic system has an arm capable of grabbing an object for a remote person to be nursed. Although the robotic system provides an arm to grab, it still mainly counts on remote control instead of self-positioning and navigation.
Moreover, there are relevant literatures as follows:    [1] B. Graf, M. Hans, J. Kubacki and R. D. Schraft “Robotic home assistant Care-O-Robot,” in Proc. of the second joint EABS/BMES conference, Houston, USA, 2002, pp. 2343-2344; and    [2] Z. Dehuai, X. Cunxi and L. Xuemei “Design and implementation of internet based health care robot system,” in Proc. of the 2005 IEEE Engineering in Medicine and Biology 27th Annual Conference, Shanghai, China, 2005, pp. 577-580.
With emphasis on the features of autonomous patrol, escort or care of a person to be nursed, the robots in the literatures [1] and [2] lacks of emergency processing feature. If a person to be nursed incurs an accident and there's no way that the robots are aware of that, no relevant countermeasure can be taken at all.